ʻĀkoʻakoʻa News

A month of restoration milestones

June 3, 2024

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There are many different methods of coral restoration, and within each method, there are different steps in the process. In our coral nursery, and with our partners working in 3RC raceways, we don't just rehabilitate corals, or breed corals, or test corals, or reattach corals. We do all of those, and more! Last month, ʻĀkoʻakoʻa saw two major milestones: the first spawning event in the nursery - a critical step in larval propagation and resilience testing - and our first-ever outplanted corals! More on each of these exciting milestones below.

Coral Spawning

Corals are animals, and just like other animals, they reproduce on their own schedules! On the morning of May 23rd, we observed several colonies of Pocillopora meandrina (cauliflower coral) and Pocillopora grandis (antler coral) spawning in our raceways at the Ridge to Reef Restoration Center (3RC). Gametes were collected, cross-fertilized in vitro, reared into larvae, and induced to settle on substrate tiles. These corals will be captively reared into juveniles and utilized in preliminary rounds of thermal testing experiments, where they will be subjected to varying water temperatures to understand their thresholds for bleaching.

Here you can see an adult colony of Pocillopora grandis, or antler coral, spawning inside a gamete capture container in a raceway at 3RC. The cloudiness of the water results from the sperm being concentrated inside the capture container.

Pocillopora grandis, or antler coral, spawning inside a gamete capture container

In these two pictures, you can see an adult colony of Pocillopora grandis inside a gamete capture container as viewed through a surface viewing lens. Sperm was released from the capture container to clarify the water and allow for the viewing of egg release. We have circled on the images several individual eggs being released and floating to the surface. This is coral reproduction in action!

Coral Outplanting

Earlier this year, a subset of corals were collected from Kailua Bay from between 45 and 65ft deep. This was part of an effort carried out by the Ocean Defenders Alliance to remove debris (including old tires) from the bay. They reached out to our partners at DAR to remove the corals prior to the their tire removal. The corals, mostly Porites lobata or lobe coral, were brought to the nursery to encourage growth and wound healing until they were ready to be outplanted back to reef near where they were collected from.

In being placed back on their reef of origin, the corals were attached using a mixture of cement, sand, and xantham gum. The ʻĀkoʻakoʻa restoration team has been testing different mixtures of ingredients for attachment in order to reduce cement pluming while still maintaining a strong bond.

Here is an example of what one coral colony looked like before it had been rehabilitated, and after outplanting.

A recently-collected coral head being placed into a raceway
That same coral head after being outplanted back on the reef, seen from a different angle